1. Technical Field
The disclosure generally relates to lenses, particularly, to lenses employed in direct-type backlight modules, which can evenly diffuse light emitted from LED packages of the direct-type backlight module.
2. Description of Related Art
A typical backlight module includes a substrate, a plurality of light emitting diode (LED) packages arranged on the substrate, and a light diffusion board spaced from and located over the LED packages.
However, each LED package generates a smooth round light field, and the light emitted from the LED package is mainly concentrated at a center thereof. The light at a periphery of the LED package is relatively poor to illuminate. Therefore, the light emitted from the LED packages can not be uniformly emitted into the light diffusion board. When this happens, the performance of the backlight module will be unfavorably affected.
What is needed, therefore, is a lens and a direct-type backlight module having the lens which can overcome the above-described shortcomings.